1. Field of the Invention
The present invention relates to the techniques of microscopes.
2. Description of the Related Art
In recent years, instead of an ordinary white light source, a laser light source is often used in microscopes. In such cases, the laser light source is usually used for the purpose of observing a sample while precisely controlling the position or area of irradiation, not for the purpose of simply irradiating the sample. Microscopes such as laser scanning microscopes are known to be used for this purpose.
In laser scanning microscopes, the irradiation area of a laser is directly relevant to the resolution. For this reason, it is very important to precisely control the laser light.
Furthermore, there are some cases in which the laser light is used for the purpose of stimulation of the sample, not for the purpose of observation. This is known as “light stimulation”, and it has been an important method in recent biological research.
Also, when laser light is used for this light stimulation, it is important to control the position or area of irradiation. In addition to that, it is required that the irradiation area be uniformly irradiated with the laser light.
A technique of irradiating a reasonably wide irradiation area with the laser light is disclosed in Japanese Application Publication No. 2007-334319. In Japanese Application Publication No. 2007-334319, an optical system for adjusting a numerical aperture is insertably and removably provided at an earlier stage of a galvanomirror. By means of that optical system, the irradiation area is adjustable. Having said that, as the laser has the intensity distribution known as the “Gaussian profile”, it is difficult to uniformly irradiate the irradiation area with the method disclosed in Japanese Application Publication No. 2007-334319.